x264/x265 encoding threads ?!

[Selur]

But why x264 does the job?(same file!)

What? No clue what that is intended to say.

Please share details.
I have no clue whether there are other error messages that are shown or what settings you are using.
I only know you are trying to convert an .264 file to .265 with x265 and that fails because the analysis of your input fails.
That analysis should already report the missing 'Frame count' entry.

Cu Selur